The broad objective of this research is to obtain a better understanding of the structure and function of the genetic material in man. This will be approached by studying the inheritance of cytogenetic markers in families who are also tested for sickle cell hemoglobin, HL-A tissue antigens, red cell blood groups and polymorphic enzymes. A major goal of the research is to detect linkage between the cytogenetic markers and other genetic markers in blood and thus be able to assign specific genes to specific chromosomes. If the chromosome carrying the hemoglobin beta chain gene could be identified, prenatal diagnosis of sickle cell anemia would be possible. In order to maximize the number of cytogenetic markers available for study in each family, quinacrine fluorescence and modified Giemsa techniques will be used to reveal chromosomal polymorphisms. It is hoped that cytogenetic markers identified in the families studied may eventually be used to monitor bone marrow transplants in sickle cell anemia patients.